The present invention relates to an elastic ring applicator for ligating anatomical elements, and more specifically relates to such an instrument which further includes a highly sensitive signaling means for alerting the surgeon when the applicator is about to deposit the elastic ring.
The applicator preferably also includes means for intraabdominally anesthetizing an anatomical element and for internally viewing the ligation procedure.
Although this instrument is particularly useful for performing female sterilization procedures involving the Fallopian tubes, it may be applied to the vas deferens in the human male, and to other anatomical structures.
Tubal ligation instruments have found world wide acceptance for a wide variety of purposes, but in particular have been used for sterilization. In the U.S. Pat. No. 3,834,392, granted to Lampman et al on Sep. 10, 1974, a laparoscope system is disclosed whereby a single unit contains the power source to provide illumination, oscillatory electrical power and CO.sub.2 gas for laparoscopy. CO.sub.2 gas under pressure is passed into the body through a needle. A trocar and cannula are inserted into the gas-filled abdominal cavity. A laparoscope connected to a source of illumination is inserted into the body cavity through the cannula. The Fallopian tubes are then identified and forceps are inserted through the cannula into the body cavity. The forceps are manipulated to successively close the passage through each Fallopian tube either by means of sending electrical oscillations through the forceps to simultaneously cut, seal and cauterize each tube in turn, or by means of a special type of clamp which clamps the passage shut.
U.S. Pat. No. 4,230,116 to Watson, granted Oct. 28, 1980, shows a tubal ligation instrument with anesthesia means for ligating anatomical elements such as Fallopian tubes. The utilization of anesthesia capabilities in such an instrument is advantageous since the areas being ligated are otherwise subjected to minor discomfort.
Like other tubal ligation instruments the Watson device discloses the use of an inner tube and an outer tube together with a biasing means, typically a helical compression spring, to warn the surgeon of the impending discharge of the elastic ring. Such a spring, however, is not helpful during the loading of elastic rings, particularly when spring resistance is counted upon to provide the necessary resistance for ring loading onto the inner tube.
Watson discloses that elastic rings are loaded onto the distal end of an inner tube by forcing them with a conical ring dilator. The inner tube is caused to protrude from the outer tube, a distance equal to the width(s) of the ring(s) placed on the inner tube. However, only the force of the spring causes the inner tube to protrude beyond the outer tube. Thus, after extended use of the instrument the spring sometimes weakens to such an extent that it becomes difficult or impossible to load rings onto the inner tube.
Further, the spring plays an important role in the surgeon's use of the Watson device. Upon intraabdominal insertion of the instrument, the surgeon retracts the slidable gripping means to a position of encountering the resistance of the helical spring. In this way, the surgeon is able to feel when the instrument is in proper orientation for applying anesthesia. Furthermore, the surgeon, upon encountering the resistance due to the spring, is informed by the yieldable resistance that he encounters that the elastic ring is about to be ejected from the inner tube. However, after the spring has become weakened after extended use it is capable of giving a false resistance feel which could even result in the surgeon's premature ejection of a ring.
Thirdly, the spring, with its helical shape and many crevices, presents a cleaning problem.
Another cleaning problem encountered in the Watson device concerns the slots and the closed end of the inner tube member. These slots can also become caked with dried blood, etc., hindering use of the instrument. The end can also become caked with blood, etc., resulting in premature release of the ring on subsequent operations.
A further problem with the Watson device concerns the size of the incision necessary to insert the instrument. The diameter of the outer housing tube in the Watson device is approximately one-half inch. Thus, a rather large trocar has been necessary to perform the ligation procedure. This sometimes causes serious psychological problems for the patient undergoing the ligation operation. The trauma to the patient is greater due to the incision diameter. There is also a greater chance of herniation due to the larger incision.
A further problem with the Watson device concerns the rotation of the device within the cannula. It is advantageous to rotate the device within the cannula to grasp the anatomical element at the proper location. If the device is tightly held by the cannula valve, both the device and the cannula must rotate to grasp the anatomical element in the proper location. If the incision is made as small as possible to prevent gas leakage, it becomes difficult to rotate the cannula in the incision. If the incision is enlarged to permit rotation of the cannula, there may be leakage of gas from the cavity. The alternative method of rotation, holding the cannula while the device is rotated, requires an additional pair of hands which makes use of the instrument more difficult and may result in contamination of the sterile field.
A further problem with the Watson device is the disassembly and assembly of the device during maintenance and cleaning. In order to disassemble the device, two steps must be performed; removal of the pin and unscrewing the inner tube. In order to assemble the device, five elements must be aligned; the hole in the inner member, the inner tube slot, the outer tube slot, the hole in the slidable finger grip and the pin.